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cc65/libsrc/nes/tgi/nes-64-56-2.s
Oliver Schmidt 2c975d3642 Create static drivers directly from source files.
Up to now static drivers were created via co65 from dynamic drivers. However there was an issue with that approach:

The dynamic drivers are "o65 simple files" which obligates that they start with the 'code' segment. However dynamic drivers need to start with the module header - which is written to. For dynamic drivers this isn't more than a conceptual issue because they are always contain a 'data' segment and may therefore only be loaded into writable memory.

However when dynamic drivers are converted to static drivers using co65 then that issue becomes a real problem as then the 'code' segment may end up in non-writable memory - and thus writing to the module header fails.

Instead of changing the way dynamic drivers work I opted to rather make static driver creation totally independent from dynamic drivers. This allows to place the module header in the 'data' segment (see 'module.mac').
2014-06-04 23:50:18 +02:00

498 lines
13 KiB
ArmAsm

;
; Graphics driver for the lores 64x56x2 mode on the NES
;
; Stefan Haubenthal, 2009-03-10
; Based on Maciej Witkowiak's line routine.
;
.include "zeropage.inc"
.include "tgi-kernel.inc"
.include "tgi-error.inc"
.include "nes.inc"
.include "get_tv.inc"
.import _clrscr, setcursor, putchar
.import paldata
.macpack generic
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table and constants.
module_header _nes_64_56_2_tgi
; First part of the header is a structure that has a magic and defines the
; capabilities of the driver
.byte $74, $67, $69 ; "tgi"
.byte TGI_API_VERSION ; TGI API version number
.addr $0000 ; Library reference
xres: .word charsperline*2 ; Max X resolution
yres: .word 56 ; Max Y resolution
.byte 2 ; Number of drawing colors
.byte 1 ; Number of screens available
.byte 2 ; System font X size
.byte 2 ; System font Y size
.word $0100 ; Aspect ratio
.byte 0 ; TGI driver flags
; Next comes the jump table. Currently all entries must be valid and may point
; to an RTS for test versions (function not implemented).
.addr INSTALL
.addr UNINSTALL
.addr INIT
.addr DONE
.addr GETERROR
.addr CONTROL
.addr CLEAR
.addr SETVIEWPAGE
.addr SETDRAWPAGE
.addr SETCOLOR
.addr SETPALETTE
.addr GETPALETTE
.addr GETDEFPALETTE
.addr SETPIXEL
.addr GETPIXEL
.addr LINE
.addr BAR
.addr TEXTSTYLE
.addr OUTTEXT
.addr 0 ; IRQ entry is unused
; ------------------------------------------------------------------------
; Data.
; Variables mapped to the zero page segment variables. Some of these are
; used for passing parameters to the driver.
X1 = ptr1
Y1 = ptr2
X2 = ptr3
Y2 = ptr4
RADIUS = tmp1
ADDR = tmp1
TEMP = tmp3
TEMP2 = tmp4
TEMP3 = sreg
TEMP4 = sreg+1
; Line routine stuff (must be on zpage)
PB = ptr3 ; (2) LINE
UB = ptr4 ; (2) LINE
ERR = regsave ; (2) LINE
NX = regsave+2 ; (2) LINE
; Absolute variables used in the code
.bss
MEM: .res charsperline*2*56/4
MEMEND:
ERROR: .res 1 ; Error code
COLOR: .res 1 ; Current color
PALETTE: .res 2 ; The current palette
; Line routine stuff
OGora:
COUNT: .res 2
OUkos:
NY: .res 2
Y3:
DX: .res 1
DY: .res 1
AY: .res 1
; Constants and tables
.rodata
DEFPALETTE: .byte $0, $1
OFFSET: .byte 8, 4, 2, 1
; 00 00 00 00 01 01 01 01
; 00 01 10 11 00 01 10 11
CODE: .byte 32, 29, 26, 25, 28, 24+128, 31+128, 30+128
; 10 10 10 10 11 11 11 11
; 00 01 10 11 00 01 10 11
.byte 30, 31, 24, 28+128, 25+128, 26+128, 29+128, 32+128
.code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. May
; initialize anything that has to be done just once. Is probably empty
; most of the time.
;
; Must set an error code: NO
;
INSTALL:
jsr _get_tv
cmp #TV::NTSC
beq ntsc
; TODO ROM!
inc yres
inc yres
ntsc:; rts
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory. May
; clean up anything done by INSTALL but is probably empty most of the time.
;
; Must set an error code: NO
;
UNINSTALL:
rts
; ------------------------------------------------------------------------
; INIT: Changes an already installed device from text mode to graphics
; mode.
; Note that INIT/DONE may be called multiple times while the driver
; is loaded, while INSTALL is only called once, so any code that is needed
; to initializes variables and so on must go here. Setting palette and
; clearing the screen is not needed because this is called by the graphics
; kernel later.
; The graphics kernel will never call INIT when a graphics mode is already
; active, so there is no need to protect against that.
;
; Must set an error code: YES
;
INIT:
; Done, reset the error code
lda #TGI_ERR_OK
sta ERROR
; rts
; ------------------------------------------------------------------------
; DONE: Will be called to switch the graphics device back into text mode.
; The graphics kernel will never call DONE when no graphics mode is active,
; so there is no need to protect against that.
;
; Must set an error code: NO
;
DONE:
rts
; ------------------------------------------------------------------------
; GETERROR: Return the error code in A and clear it.
GETERROR:
lda ERROR
ldx #TGI_ERR_OK
stx ERROR
rts
; ------------------------------------------------------------------------
; CONTROL: Platform/driver specific entry point.
;
; Must set an error code: YES
;
CONTROL:
lda #TGI_ERR_INV_FUNC
sta ERROR
rts
; ------------------------------------------------------------------------
; CLEAR: Clears the screen.
;
; Must set an error code: NO
;
CLEAR:
ldx #<MEM
stx TEMP
ldx #>MEM
stx TEMP+1
lda #0
tay
@L1: sta (TEMP),y
iny
bne @L1
inc TEMP+1
inx
cpx #>MEMEND
bne @L1
jmp _clrscr
; ------------------------------------------------------------------------
; SETCOLOR: Set the drawing color (in A). The new color is already checked
; to be in a valid range (0..maxcolor-1).
;
; Must set an error code: NO (will only be called if color ok)
;
SETCOLOR:
sta COLOR
; rts
; ------------------------------------------------------------------------
; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
; The page number is already checked to be valid by the graphics kernel.
;
; Must set an error code: NO (will only be called if page ok)
;
SETVIEWPAGE:
; ------------------------------------------------------------------------
; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
; The page number is already checked to be valid by the graphics kernel.
;
; Must set an error code: NO (will only be called if page ok)
;
SETDRAWPAGE:
rts
; ------------------------------------------------------------------------
; SETPALETTE: Set the palette (not available with all drivers/hardware).
; A pointer to the palette is passed in ptr1. Must set an error if palettes
; are not supported
;
; Must set an error code: YES
;
SETPALETTE:
; Wait for v-blank
@wait: lda PPU_STATUS
bpl @wait
lda #$3F
sta PPU_VRAM_ADDR2
lda #$00
sta PPU_VRAM_ADDR2
ldy #0
lda (ptr1),y
sta PALETTE
tax
lda paldata,x
; sta PPU_VRAM_IO
iny
lda (ptr1),y
sta PALETTE+1
tax
lda paldata,x
sta PPU_VRAM_IO
lda #TGI_ERR_OK
sta ERROR
rts
; ------------------------------------------------------------------------
; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
; set the palette should return the default palette here, so there's no
; way for this function to fail.
;
; Must set an error code: NO
;
GETPALETTE:
lda #<PALETTE
ldx #>PALETTE
rts
; ------------------------------------------------------------------------
; GETDEFPALETTE: Return the default palette for the driver in A/X. All
; drivers should return something reasonable here, even drivers that don't
; support palettes, otherwise the caller has no way to determine the colors
; of the (not changeable) palette.
;
; Must set an error code: NO (all drivers must have a default palette)
;
GETDEFPALETTE:
lda #<DEFPALETTE
ldx #>DEFPALETTE
rts
; ------------------------------------------------------------------------
; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
; color. The coordinates passed to this function are never outside the
; visible screen area, so there is no need for clipping inside this function.
;
; Must set an error code: NO
;
SETPIXEL:
ldx Y1 ; y+2<yres
inx
inx
cpx yres
bcc @L2
ldx X1 ; x+2<xres
inx
inx
cpx xres
bcc @L2
rts
@L2: lda X1
lsr
tay
lda Y1
lsr
tax
clc
jsr setcursor
jsr CALC
ldx COLOR
bne @set2
eor #%00001111
@set2: sta TEMP3
lda (TEMP),y
ldx COLOR
bne @set
and TEMP3
.byte $2c
@set: ora TEMP3
sta (TEMP),y
tax
lda CODE,x
@normal:jmp putchar
; ------------------------------------------------------------------------
; GETPIXEL: Read the color value of a pixel and return it in A/X. The
; coordinates passed to this function are never outside the visible screen
; area, so there is no need for clipping inside this function.
GETPIXEL:
jsr CALC
sta TEMP3
lda (TEMP),y
and TEMP3
beq @L1
lda #1
@L1: ldx #0
rts
; ------------------------------------------------------------------------
; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
; Contrary to most other functions, the graphics kernel will sort and clip
; the coordinates before calling the driver, so on entry the following
; conditions are valid:
; X1 <= X2
; Y1 <= Y2
; (X1 >= 0) && (X1 < XRES)
; (X2 >= 0) && (X2 < XRES)
; (Y1 >= 0) && (Y1 < YRES)
; (Y2 >= 0) && (Y2 < YRES)
;
; Must set an error code: NO
;
BAR:
inc Y2
@L1: lda X1
pha
@L2: jsr SETPIXEL
inc X1
lda X2
cmp X1
bne @L2
pla
sta X1
inc Y1
lda Y2
cmp Y1
bne @L1
rts
; ------------------------------------------------------------------------
; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
; direction is passend in X/Y, the text direction is passed in A.
;
; Must set an error code: NO
;
TEXTSTYLE:
rts
; ------------------------------------------------------------------------
; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
; current text style. The text to output is given as a zero terminated
; string with address in ptr3.
;
; Must set an error code: NO
;
OUTTEXT:
lda ptr1
lsr
tay
lda ptr2
lsr
tax
clc
jsr setcursor
ldy #0
@L1: lda (ptr3),y
jsr putchar
iny
cmp #$0
bne @L1
rts
; ------------------------------------------------------------------------
; Calculate all variables to plot the pixel at X1/Y1. If the point is out
; of range, a carry is returned and INRANGE is set to a value !0 zero. If
; the coordinates are valid, INRANGE is zero and the carry clear.
CALC: lda xres
sta TEMP
lda #0
sta TEMP+1
ldy Y1
@L1: lda TEMP
add xres
lsr
sta TEMP
lda TEMP+1
adc #0
lsr
sta TEMP+1
dey
bne @L1
lda TEMP
add X1
lsr
sta TEMP
lda TEMP+1
adc #0
lsr
sta TEMP+1
lda TEMP
add #<MEM
sta TEMP
lda TEMP+1
adc #>MEM
sta TEMP+1
lda X1
and #%00000001
sta TEMP3
lda Y1
asl
and #%00000010
ora TEMP3
tax
lda OFFSET,x
rts
; ------------------------------------------------------------------------
.include "../../tgi/tgidrv_line.inc"